Knowledge vs. Phenomenon is the basic distinction. Now we need to do a sorting exercise. Where would I put sensations? Broadly under phenomena. Where would I put experience? Broadly under knowledge. There is more to be said about what we consider as experience and what as knowledge. But I'm not equipped to do that.
If I have experience playing the violin, I have some knowledge of it. It also helps me in acquiring new knowledge, like playing the cello.
The distinction you are talking about becomes important when we are talking about "knowing that" or "declarative knowledge". The theory of thermodynamics is distinct from the methods of acquiring that theory, like experiments, equations etc. But when we talk of experience, we are not beholden to that distinction. The knowledge of cycling and the means of acquiring it are logically distinguishable but not empirically separable.
But I don't think I'm arguing against Multiple Worlds Theory.
Not knowing about x is no proof for the non existence of x. (That's one part of the multiple world claim).
But my claim is this. Either there are some common, (or relatable) set of distinctions in our deeds and words and therefore I can recognize it as an experience. Or, I can only see it as an event needing some explanation.
Either the contortions on someone's face are indications of grief (assuming I know grief), or, if I don't know what grief is, then, they are merely some physiological events needing some explanation. We don't have a way out of this either/or situation.
Thank you very much for this detailed and careful response. Probably, this requires another post altogether to respond. But a few clarifications for now:
1. I have corrected the sentence beginning "If we can maneuver an automobile..." Sorry about the shoddy editing.
2. Comportment: You had me there! I've mostly encountered that word in Heidegger translations. And clearly, the ambiguity shows. Let me change that.
3. Now, a few substantive issues:
Take the case of an astronaut returning from space travel and reporting things. Let’s assume, she says, “you don’t experience gravity in outer space”. In day-to-day contexts this is a perfectly harmless and fairly accurate description. The problem comes when we take this sentence to refer to something like “an experience of gravity”. What the astronaut experiences in outer space is not the presence or absence of gravity. What she experiences is that, unlike on Earth, you float in space. A bunch of related experiences like these are then explained using a very elaborate structure of ideas like gravity. So, “gravity” is not what you experience, because ideas like gravity are not things that you can experience. It is an explanation to account for many experiences in a systematic way.
A similar line of reasoning holds for 'existential terror' and 'depression' and many other such abstractions we use to talk about our experience. Again, as I said, this kind of talk is perfectly harmless in day-to-day contexts because we all understand existential terror to only mean some special kind of fear or terror. However, when this kind of talk enters specialist vocabulary, like in the humanities, philosophy and our educated discourse, it creates problems.
With examples like "I am experiencing a headache", there is no real problem but bloated language. What we mean when we say "I am experiencing a headache" is simply that "I have a headache". We are reporting on a sensation, which is private and episodic. Of course, there is no problem in using the bloated language. But then, supposing you do not have a headache now, would you want to claim that you have no experience with headaches? Clearly not. That would mean the following: you do make a distinction between sensation and experience. You can report on the sensation of a headache. But then, if you are not talking about the particular sensation, but a general understanding of what it is to have things like headaches, you would say "I know what it is to have a headache. So do not lecture me on that!". In this latter instance, you do not mean the having of a sensation, but the ability to understand, recognize or handle things like headaches.
I hope you will concede the following: it is meaningless to talk about someone’s experience as being true or false. Sentences like “he had a true experience” and “her experience is false” sounds wrong. Now, this can be the case only if experience is not equated with explanations. Explanations can be true or false, not experiences.
Some minor clarifications: if a card player cannot talk about a game of cards, then, either we must have some other token by which we can see that he knows his game or we have to give up on our insistence that he has experience with card games. This may sound awkward but I’ll try: It is meaningless to hold on to the picture that, on the one hand, we have absolutely no way of figuring out whether someone has experience with card games, and on the other, that the man in question has experience with card games.
And, the last bit: imagine a person with absolutely no knowledge of Western classical music sitting through a concert. Someone who knows the music has experienced a great symphony. But would you say that our man has also experienced it? No. He has experienced only a jumble of sounds. This shows that to describe someone as having had an experience, we need to complete the sentence with an object (a grammatical object, but also one that can properly be called an object of the experience). “We experienced (enjoyed, listened to...) a great symphony today”. Or, in the case of our man, “He experienced a great cacophony of sounds today”.
So, it is not merely about which word one chooses instead of the word 'experience'. It is about what we think experience is and what it is not.
Some people argue that their experiences are unique and therefore others cannot be privy to it. In politics and issues relating to righting historical wrongs, such arguments then become a conversation stopper. So we need an understanding of experience which is sensitive to the fact that others' experiences are different while not allowing for it to be claimed as unique and private.
Experience is also a way to acquire knowledge. The crucial distinction is that experience is not a psychological event, like say, trauma or neurosis, could be a psychological event.
And regarding the game of cards, I'm agnostic about whether there is or there is no platonic model. But the game, or any meaningful system, has a convention, which cannot be reduced to the individual memory or knowledge people have about it. That's the force behind saying something is a convention.
The only problem is these examples render the very idea of experience superfluous.
And your test case about molestation is such a morally charged issue that I would not hazard logic chopping on it yet. (Hint: if the victim has some way of making sense of the event, it is an experience. If the victim has not emerged from the shock of it, then it is a trauma, a raw event, and not an experience).